How do you go about confirming a FI computer is working? I have read that there a replacment boards out the but not sure where to find them. I just baught a 73 1.7 914 and am working to get the injection up and running. Help.....

Thanks
Brandon

Brandon,
http://914ltd.com/ Brad Mayeur Phone number (309) 694-1797,
Brad is the FI Guy, I was ready to trash all the injection parts on my wife's 73 2.0 914 and he talked me off the ledge. an amazing guy. There are also a ton references so that you can read about The FI theory of operation, such as the PB anders Rennlist posting; http://members.rennlist.com/pbanders/djetparts.htm, Jeff Bowlsby can build you a new harness if needed, Marren Fuel injection can flow your injectors in a quick turn around time if needed. BUT The biggest thing I've noticed is that the guys here on 914 World will bend over backwards to help you.

By the way I've not really been here that long myself but
According to Brad the ECU rarely is the issue.

I'm not sure if this the right way to test the system but I first checked all the component voltages per PB Anders' WEB site (via the main wiring harness as he specifies) then I used the wiring harness from Jeff Bowlsby's site at http://bowlsby.net/914/WiringHarnesses/ to bench test the entire system. We powered the system with an external 12V power supply, spun the distributer with a variable speed drill, drove the MPS pressure with a Harbor Freight hand pump, and measured the injector duration with an oscilloscope (via a resistor and unbent paperclip to the top of the injector connector). We varied manifold pressure, speed, and thottle switch position to make sure the injector duration was trending in the right direction.

I haven't had this system on an engine yet, so I can't say this a valid test, but it sure gives me the warm and fuzzies. I also didn't do anything to verify the head temp sensor had an effect on the injectors.

I have to give credit to my physicist friend who supplied all the equipent and help me set it up.

Also, think about getting a new Dave Sprinkle built TPS board (brand new - better than OEM) from www.914Rubber.com and replace the one in your TPS.

If the MPS is questionable, check Racer Chris's recent developments on replacement diaphragms for the MPSs on his www.Tangerineracing.com site.

Mark De Bernardi, AKA "McMark" from Original Customs, another site vendor has extensive knowledge and a few tricks up his sleeve.

All 3 are members here.

www.witchhunter.com is also a quick & reliable service for FI Injectors - did a set of my 1.7s a couple of years ago...

About everything you need to know about D-Jet is here: http://bowlsby.net/914/Classic/zTN_Man06.pdf

Probably the most important point in Bowlsby's article is the ECU is generally the last thing to look at.

Olin

Wow thanks folks for the fast reply, I have been messing with 911s and Webers for years but never played with FI and I would really like to get this working.....need all of the fuel and vacuum hoses as they are nasty and the fuel pump is gone like in not there, so I need to find one. Is there an after market solution for both problems?

We just installed a '75-76 fuel pump in a customer's '73, in the engine compartment.
Switching from a 3 port to a two port pump saved big $$.
Sourced from NAPA, price of the Bosch pump was under $100.

Do you just block off the return from the pump to the tank to the tank?

Thanks
Brandon

If you go to the two-port pump, you just eliminate the Y where the "R" port on the pump connects. So the line from the fuel pressure regulator just goes back to the tank.

There is a tester that you can plug into the ECU to test it in the car. I don't know who near you has one, though.

--DD